As this type of tape cartridge, there is known a tape cartridge (see PTL 1) that is mounted on a tape printer such that a thermal head (print head) is inserted into a through opening (insertion opening) formed in a cartridge case. Then, the thermal head is pressed to a platen roller (platen) of the tape cartridge, so that the tape printer is brought into a print state.
This tape cartridge has an external shape that is defined by the cartridge case including an upper case and a seat-side lower case. The upper case has an upper through opening into which the thermal head is inserted. The lower case has a lower through opening into which the thermal head is inserted. The upper through opening is formed such that a contact portion of a platen roller that is brought into contact with the thermal head protrudes. The lower through opening is formed to extend by a certain length relative to the upper through opening such that the contact portion of the platen roller does not protrude. Accordingly, when the tape cartridge is mounted on the tape printer, an ink ribbon that is located near the platen roller is prevented from being hooked to another member.
In this tape printer with the tape cartridge mounted, seating of the tape cartridge is adjusted such that the thermal head (head body) and the platen roller (rubber roller) have equivalent heights and that a lower end portion of the thermal head does not interfere with an edge of the lower case defining the lower through opening.